The 2008 Super Duty came to the diesel battle armed with an extensively updated diesel engine option. The new 6.4 improves on several key areas where its 6.0 predecessor had problems. One of the biggest problem areas with the old engine were the unreliable HEUI (hydro-electric unit) injectors. In and of themselves, they're not an unreliable design, but in order to compete with GM's relatively silent Duramax, the engine software was programmed to do multiple "pre-injections" to quiet the combustion process. The dated HEUI design was not engineered for such a duty cycle, and injector failures were commonplace on early 6.0s.
Well, Ford took no chances with the 6.4, going straight to state-of-the-art Piezo injectors, which are capable of extremely high fuel pressures as well as multiple injection pulses. Add sequential turbos to the mix, and you've got a potent combination good for 350 horsepower and 650 lb.-ft. of torque. Unfortunately, this powerful new engine is still bolted to the 5-speed TorqShift transmission.
Domestic truck owners are so fiercely brand-loyal, that no matter how much I or anyone else extolls the virtues of competitors, it's pretty much just noise. However, from an objective standpoint, the new LMM Duramax and 6-speed Allison seem like the most formidable powertrain combo, even though Ford is claiming the highest towing capacity. After seeing the front of the new Super Duty with a ludicrous number of heat exchangers and coolers, I wouldn't doubt its capability.
For now, 3/4 and 1-ton diesel trucks are the exclusive domain of the domestics. Although rumors have been rumbling about Toyota and Nissan getting into the game, and even tacit confirmation from company executives, there's still no metal in the showrooms and rubber on the road. Let's hope the 6.4 holds up to its promise of reliable performance where its predecessor unfortunately fell short.